ML20236X994
| ML20236X994 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 07/31/1998 |
| From: | Yawar Faraz NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20236X980 | List: |
| References | |
| NUDOCS 9808110074 | |
| Download: ML20236X994 (4) | |
Text
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UNITED STATES E
NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 2055M001
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July 31, 1998 DOCKET:
70-7002 CERTIFICATE HOLDER:
United States Enrichment Corporation Portsmouth Gaseous Diffusion Plant Portsmouth, OH
SUBJECT:
COMPLIANCE EVALUATION REPORT: APPLICATION DATED JUNE 11,1998, COMPLIANCE PLAN ISSUE 11 REVISION BACKGROUND By letter dated June 11,1998, the United States Enrichment Corporation (USEC) submitted a Certificate Amendment Request (CAR) regarding the Certificate of Compliance for the Portsmouth Gaseous Diffusion Plant (PORTS). The request is to delete the requirement in The Plan for Achieving Compliance with NRC Regulations at the Portsmouth Gaseous Diffusion Plant (Compliance Plan) Issue 11, Plan of Action and Schedule, to install evacuation horns / lights in the X-744H warehouse and to tie them to the X-744G warehouse Criticality Accident Alarm System (CAAS), by July 1,1998. Prior to requesting approval from the NRC for changes to the Plan of Action and Schedule section of the Compliance Plan, USEC is required to obtain the Department of Energy's (DOE's) approval. As such, USEC in a letter dated May 7,1998, requested DOE approval of the change. DOE's approval was granted on May '29,1998.
Issue 11 of the Compliance Plan was originally developed to ensure that workers in X-744H would be alerted immediately if an inadvertent criticality occurred in X-744H. The criticality would be detected by the CAAS cluster of instruments located in X-744G. However, according to USEC, recent operational changes, which includes the transfer of fissile material operations of concern from X-744H to another facility which is already covered by a CAAS, and the intrinsic nature of the residual contaminated material stored in X-744H, do not warrant CAAS coverage since a criticality accident in this facility is not credible.
Recognizing that the NRC would not have sufficient time to review and approve the amendment before July 1,1998, USEC submitted a Request for Enforcement Discretion on June 18,1998.
As stated in its response dated July 9,1998, the NRC determined that a Notice of Enforcement Discretion (NOED) was not appropriate since Section Vll.C of the " General Statement of Policy and Procedures for NRC Enforcement Actions," (Enforcement Policy), NUREG-1600, provides, in part, that an NOED may be granted if a licensee's compliance with a Technical Specification Limiting Condition for Operation or with other license condition would involve an unnecessary plant transient, or unnecessary delays in plant startup, without corresponding health and safety benefit. In this case, not installing and tying the evacuation horns / lights in X-744H to the X-744G CAAS does not involve any such transients or delays. However, recognizing that a violation of an NRC requirement would legally exist from July 1,1998, until the NRC's final decision is issued on this matter, the NRC decided to exercise enforcement discretion under Section Vll.B.1 of the Enforcement Policy until NRC's final decision on this case.
I 9808110074 990731 PDR ADOCK 07007002 i
C PDR a
2 DISCUSSION A CAAS is provided to detect and alert personnelif a criticality accident should occur. The system utilizes horns with distinctive audible signal and lights to notify personnelir the affected area and to initiate evacuation, thereby reducing the total personnel exposure to emitted radiation over the course of the accident. At PORTS, by technical safety requirement, CAAS detection is required for all areas containing more than 700 grams of U-235 at an enrichment exceeding 1.0 weight percent (wt%) and CAAS horn audibility is required for all areas where the maximum foreseeable absorbed dose in free air from a criticality exceeds 12 rad. In addition, according to Section 5.2.2.5 of the PORTS Safety Analysis Report (SAR), areas with an areal density of less than 50 grams of U-235 in any square meter cf floor or ground area, a volume concentration less than 5 grams of U-235 in any 10-liter volume, or material that is packaged and stored in compliance with 10 CFR 71 " Packaging and Transportation of Radioactive Material," or specifically exempt according to 10 CFR 71.10 " Exemption for Low-Levei Materials," can be shown by evaluation not to require criticality alarm coverage. It should be noted that SAR Section 5.2.2.5 also implies that areas that do not contain any operations involving uranium enriched to 1.0 wt% or higher U-235 or more than 15 grams U-235, are not required to have CAAS coverage. It should alr.o be noted that Engineering Evaluation EV-X-832-97-001 dated May 26,1998, prepa ed by USEC to support this amendment, states f
that if no single piece of equipment contains greater than 15 grams of U-235, and the total l
amount of U-235 is less than 700 grams and less than 50 grams U-235 per square meter in the l
north end of X-744H where K-25 (shutdown gaseous diffusion plant in Oak Ridge Tennessee) i equipment is stored, then CAAS coverage is not required.
Issue 11 of the Compliance Plan required USEC to install evacuation horns / lights in the X-744H
, warehouse and to tie them to the existing CAAS in X-744G that provides detection coverage for X-744H. This Compliance Plan requirement was based on the premise that even though an I
inadvertent crit;cality in X-744H would be detected by the CAAS monitor in X-744G, tM existing evacuation horns / lights tied to the X-744G CAAS may not be audible / visible in X-744H.
According to USEC, since the Compliance Plan issue 11 was developed, operations in tha X-744H warehouse have been modified such that they currently do not meet the minimum criteria for requiring CAAS coverage (criticality detection and alarm audibility / visibility) in that building; i.e. a criticality is no longer credible in X-744H.
According to USEC, there are several areas at PORTS in which a criticality accident is not credible, such as those areas that do not normally contain more than 700 grams of U-235, at an enrichment of 1.0 wt% or more (criticality significant quantities of uranium), at any one time.
However, if these facilities are in close proximity (within 200 feet) to other facilities that have areas which handle criticality significant quantities of uranium, then alarm audibility needs to be provided even though a criticality detection capability may not be necessary. This is to allow workers to promptly evacuate the area formed by a 200 foot radius from the point of criticality, l
l since the dose from a criticality within this area, for the entire duration of the excursion, can be significant. For facilities where such a condition exists, compliance for audibility is attained by installing an evacuation horn / light in the facility that does not have areas with criticality significant quantities of uranium and by connecting it to the existing CAAS alarm system designed to detect a criticality in the nearby facility that has areas with criticality significant quantities of uranium.
The staff confirmed that there are no facilities within 200 feet of X-744H that would normally I
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have areas with criticality significant quantities of uranium at any one time. Therefore, the staff notes that X-744H is not required to be connected or slaved to an existing CAAS alarm system from the stand point of its distance to other facilities with areas containing significant quantities of uranium.
The staff has determined that under normal operating conditions, a criticality is very unlikely in X-744H since only clean equipment is stored in the warehouse. Storage includes cleaned and decontaminated parts (fixed surface contamination less than 30,000 dpm/100cm ) received 2
a from X-705 " Decontamination Building" and K-25. Staff walked through X-744H and noted a few
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labels on large pieces of equipment. None of these indicated fixed contamination greater than 2
2 30,000 dpm/10 cm or removable contamination greater than 200 dpm/10 cm. The Engineering Evaluation EV-X-832-97-001 notes that 30,000 dpm/100 cm is equivalent to i
2 2
0.03 grams U-235 / m The staff independently confirmed this value and notes that it conservatively corresponds to a uranium enrichment close to 10 wt%. The staff noted that for 0.71 (natural),50 and 100 wt% enrichments, the U-235 surface concentrations by weight are 2
0.014,0.024 and 0.019 grams U-235/m, respectively. These are alllower than the 2
0.03 grams U-235/m value for 10 wt%. It should be noted that there is a procedural requirement to not store in X-744H, equipment that has on it visible contamination which usually 2
i amounts to a few thousand dpm/m ). It should also be noted that a very small fraction of the contamination on the stored parts and equipment is removable. Based on the intrinsic nature nf I
the contamination and the associated small quantities of U-235 from a criticality stand point, the l
staff concludes that it would be highly unlikely for a criticality to occur in X-744H. Even if the l
trace quantities of removable uranium is somehow removed from the surfaces of the stored l
equipment and parts, such as by means of a sprinkler system actuation during a fire, a sufficient j
quantity could not conceivably accumulate in any one location so as to cause a criticality concern.
l The staff also assessed the possibility of inadvertent storage of equipment containing criticality significant quantities of uranium in X-744H. The X-744H facility custodian and PORTS l
personnel informed the staff that prior to storage, all equipment is surveyed following i
decontamination and cleaning in X-705 and before shipment from K-25. In addition, PORTS l
personnel inspect equipment for visible contamination before storage in X-744H. The facility l
custodian for X-744H also stated that the warehouse is required to be locked when it is l
unoccupied, that access to the warehouse is limited to himself, his crew and the plant shift superintendent, and that all workers who have access to the warehouse are trained not to allow l
criticality significant quantities of uranium to be stored in the facility.
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ENVIRONMENTAL REVIEW i
l Issuance of the requested amendment to the Portsmouth Certificate of Compliance (GDP-2) to i
not require CAAS evacuation horns / lights for the X-744H warehouse is subject to the categorical exclusion provided in 10 CFR 51.22(c)(19) and will not have a significant impact on the human environment. Therefore, in accordance with 10 CFR 51.22(b), neither an environmental assessment nor an environmental impact statement is required for the proposed action.
4 CONCLUSION 3
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Based on the information provided by USEC in its CAR and the information contained in EV-X-832-97-001, and based on the staff's discussions with the facility custodian and plant personnel, the staff concludes that for normal operations, a criticality accident in the X-744H -
warehouse is very unlikely. In addition, the staff finds USEC's controls to limit the uranium content in the X-744H warehouse for maintaining nuclear criticality safety, to be acceptable. As such, the staff finds that not installing a CAAS evacuation hom/ light in X-744H and connecting it to the X-744G CAAS will not significantly impact safety at PORTS.
The Region 111 Inspection staff has no objection to this proposed action.
Princioal Contributor Yawar Faraz l
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DISTRIBUTION:(ControlNo. 340S)
Docket 70-7002 NRC File Center PUBLIC Ko'Brien, Rill MHom NMamish, OE WTroskoski, FCoB NMSS r#FCSS r# '
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